1. Field of the Invention
The present invention relates to an optical rotary adapter and an optical tomographic imaging apparatus using the optical rotary adapter. More particularly, the present invention relates to an optical rotary adapter configured to rotatably connect between optical fibers which, in order to acquire an optical tomographic image of a measuring object, guide a measuring light beam to the measuring object and guide a return light beam from the measuring object, and relates to an optical tomographic imaging apparatus which irradiates a measuring object with a light beam and which acquires an optical tomographic image of the measuring object from a return light beam reflected from the measuring object.
2. Description of the Related Art
Conventionally, there is known an optical tomographic imaging apparatus using an optical coherence tomography (OCT) measuring method as a method for acquiring a tomogram without cutting a measuring object, such as a living tissue.
The OCT measuring method is a kind of optical interferometric methods and is a measuring method which utilizes the fact that in the case where a light beam emitted from a light source is divided into a measuring light beam and a reference light beam, optical interference is detected only when the optical path lengths of the measuring light beam and the reference light beam coincide with each other within the coherence length of the light source.
Here, since the light beam used in the OCT measuring method is a near-infrared light beam which is not visually recognized, it is difficult to confirm which part of a measured region is actually exposed to the light beam. Thus, an aiming beam (aiming light beam) serving as a mark is used together with the measuring light beam (OCT signal light beam).
There are known, for example, a method in which the aiming light beam is multiplexed with the OCT signal light beam by an optical coupler outside an optical fiber interferometer (see, for example, Japanese Patent Application Laid-Open No. 2002-200037, and the like), and a method in which the aiming light beam is multiplexed with the OCT signal light beam by an optical coupler in an optical fiber interferometer (see, for example, Japanese Patent Application Laid-Open No. 2005-156540, and the like).